Environmental Quality Assessment of The Agricultural Production Area Based on Heavy Metal Risk Analysis In Soils and Crops From a Typical Economic Region, Southeastern China

BackgroundHeavy metal pollution in soil-crop system attracted great attention globally with rapid urbanization and intensive industrialization. Due to their accumulation and enrichment effects may pose a serious threat to food safety and human health, it is significant to assess environmental quality assessment of the agricultural production area before plantation. Numerous previous studies have been conducted to identify the total amount, distribution patterns and contamination levels of specific heavy metals in agricultural environment, while haven’t taken them in both soil and crop into account. Therefore, it is necessary to establish an evaluation approach to indicate the relationship between agricultural resources and farm produce, which considering the soil-crop system quality in relation to multiple heavy metals.MethodsThe soil and crop samples were collected from 370 sampling points in Taizhou City, which is a typical agricultural region located in the central of Jiangsu Province, China. After determination of heavy metals contents, the pollution status and risks of multiple heavy metals were analyzed through both single factor pollution index and Nemero comprehensive pollution index method. Subsequently, the spatial distribution and relevant risk potentials of heavy metals in both soils and crops were illustrated by using ArcGIS 10.3. The K-means clustering algorithm was then applied to quantitatively classify the environment partition with consideration of above results as main indicators. ResultsThe mean values of soil Cr, Pb, Cd, As and Hg were 66.78, 32.88, 0.23, 8.16 and 0.16 mg/kg which were much higher than their background values. Affecting by the anthropogenic activities, the average contents of soil Cd and Hg exceeded the risk screening value at a rate of 11.70% and 5.96%, respectively. The heavy metal pollution in soil and crop were inconsistent as more than 97% of the study soils were not polluted with toxic metals while 11-23% of the crop possessed safety risk with Cd and Pb. Based on the pollution assessment, approximately 83% of the study area possessed medium or higher environmental quality, which were preferable for agricultural production.ConclusionsOur results revealed that, the spatial distribution, pollution level of the heavy metals in soil-crop system were significantly influenced by industrial activities, followed by agricultural sources and transportation emissions etc. Therefore, continuous monitoring and source control for heavy metals, especially for Cd, should be conducted to ensure the environmental quality and food security.